>>> just how crucial was technology as this case unfolded? well, these pictures captured by surveillance cameras at the boston marathon ultimately led to the capture of dzhokhar tsarnaev. joining me jodie warbrick national security reporter at "the washington post." i know you had an awesome breakdown of the series of event leading to the capture of these two brothers, so walk us through it. and how crucial were the security devices identifying them? >> you know, it's really a mix as far as technology goes, because, yeah, absolutely the security camera videos and still shots were incredibly good. came from many different sources not just law enforcement stuff but retail stores and private cameras and this is what really brought us to the suspects, but a lot of this was still old fashioned police work and some dumb luck. a guy happens to see last night some blood on a tarp on a boat and that's what leads to the break of finding the second suspect. we still need the good stuff, too. >> tell me how the boat, then, played out? that was it. do we